решил проблему,
это изменение определения кода
def deconv2d(layer_input):
"""Layers used during upsampling"""
u = UpSampling2D(size=2)(layer_input)
u = Conv2D(256, kernel_size=3, strides=1, padding='same')(u)
u = Activation('relu')(u)
return u
size=1 instead of 2